flutter-localization

Add flutter_localizations (sdk) and intl: any to pubspec.yaml, set flutter: generate: true, create an l10n.yaml pointing at your ARB directory, then run flutter gen-l10n. Wire the generated AppLocalizations delegates and supportedLocales into MaterialApp.

gen-l10n generates typed, compile-time-checked accessors from ARB files with IDE autocomplete and ICU plural support. easy_localization loads JSON at runtime with string-key tr() lookups that break silently on typos, so it suits prototypes only.

The Flutter SDK exact-pins the intl version used by flutter_localizations, so declaring your own caret pin like intl: ^0.20.2 causes version solving to fail. Declare intl: any in pubspec.yaml instead.

Use ICU MessageFormat syntax in the ARB value, such as {count, plural, =0{No items} other{{count} items}}, with a @key metadata block declaring the placeholder type. The generator compiles it to an Intl.plural call with correct per-locale rules.

Wrap the widget under test in a MaterialApp that provides AppLocalizations.localizationsDelegates, supportedLocales, and an explicit locale. Assert against the translated string, not the English default, to prove the locale's ARB file actually resolves.

Do not use it for Android XML string resources, which belong to the native Android localization flow. It is also unnecessary for quick prototypes where runtime JSON loading is acceptable, though gen-l10n has similar setup cost.